The present invention relates to a semiconductor chip package and a manufacturing method thereof, and to a semiconductor chip having a configuration suitable for application to such a semiconductor chip package.
There has been developed a technique for manufacturing an approximately few hundred-μm microstructure using a micromachining technique that applies a semiconductor micro-fabrication technique. Applications to, for example, various sensors, an optical switch in an optical communication field, high-frequency (RF) parts, etc. have started.
Since such a microstructure can be fabricated by a conventional semiconductor manufacturing process, it can be integrated into a single chip.
A chip including a microstructure, in which a system having a specific function has been constructed, is referred to as “Micro-Electrical-Mechanical-Systems: MEMS” or “Micro-System-Technology: MIST” (hereinafter called simply “MEMS chip”). A so-called acceleration sensor chip is known as such a MEMS chip (refer to, for example, a patent document 1 (Japanese Patent Application Laid-Open No. He 11(1999)-135804).
According to the configuration of a piezo type acceleration sensor chip disclosed in the present document, a casement-like frame is provided. The frame includes a central portion and a beam section. The beam section extends between at least part of an inner peripheral side surface of the frame and the central portion. A weight portion is swingably supported by the central portion. A support member supports the lower surface side of the frame and surrounds the outer peripheral edge of the weight portion through a cut portion.
Since the weight portion is of a constituent portion which makes a movement in response to an external force (stress), it is also called “a movable section”. The movable section and the beam section are fabricated and mounted as an integral microstructure. The beam section is formed in a thin-walled fashion and with a narrow width.
The sensor chip having such a configuration is generally referred to as a packaged device.
A configuration example of a conventional acceleration sensor chip package will be explained below with reference to FIG. 7.
FIG. 7(A) is a schematic plan view for describing constituent elements, as viewed from the upper or top surface side of the conventional acceleration sensor chip package. Incidentally, in order to show an internal configuration thereof, the illustration of the upper surface side of a protective cover (to be described later) also called “LID” in general is omitted, and the present figure is shown as a transparent diagram. FIG. 7(B) is a typical view showing a cut area cut along alternate long and short dashed lines indicated by A-A′ of FIG. 7(A).
The acceleration sensor chip package 100 is provided with an acceleration sensor chip 110. The acceleration sensor chip 110 has electrode pads 112. The electrode pads 112 are pads for outputting signals sent from the acceleration sensor chip 110 or inputting signals to the acceleration sensor chip 110. A mechanically operated movable structure 114 is fabricated and built in the acceleration sensor chip 110.
Further, the acceleration sensor chip 110 has a sealing or encapsulating substrate 116 which seals the movable structure 114 and controls its operation. The sealing substrate 116 is bonded to a substrate 120 by an adhesive 122.
The edges of a release or open hole of the protective cover 130 are adhered to the substrate 120. The protective cover 130 defines a closed space 140 for sealing the acceleration sensor chip 110.
External terminals 150 are provided at their corresponding edges of the substrate 120. The external terminals 150 are led out from the interior of the closed space 140 defined in cooperation with the protective cover 130 to the outside thereof. The electrode pads 112 of the sensor chip 110 and the external terminals 150 are respectively electrically connected to one another by bonding wires 160 within the closed space 140.
According to the conventional acceleration sensor chip package referred to above, the acceleration sensor chip and the external terminals are electrically connected to one another by the bonding wires 160. The protective cover is used to seal the acceleration sensor chip while the bonding wires 160 are being held in the package. Thus, it is not possible to carry out a transfer mold and sealing by potting using a liquid resin, and it is difficult to make the thickness of the package thinner, thereby leading to an increase in occupied volume of the package.
With multifunctioning of electronic equipment such as a cellular phone, there has recently been a desire for the development of a technique for achieving a further reduction in the size of a semiconductor chip package including an MEMS chip in particular.